Method and apparatus for blending discrete materials



INVENTOR.

Jan. 1, 1963 A. A. M INTYRE METHOD AND APPARATUS FOR BLENDING DISCRETEMATERIALS Filed May 5. 1959 2 Sheets-Sheet 1 Iii ALEXANDER A. McINTYREBY Jan. 1, 1963 A. A. MCINTYRE 3,071,352

METHOD AND APPARATUS FOR BLENDING DISCRETE MATERIALS Filed May 5, 1959 2Sheets-Sheet 2 mun 3,; a)

FIG. 6

INVENTOR. ALEXANDER A. MCINTYRE Patented Jan. 1, 1963 ice METHGD ANDAPPARATUS FUR BLENDING DHQRETE MATEREALS Alexander A. McIntyre,Lancaster, Pa, assignor to tCapitol Products Corporation, Mechanicsburg,Pa, a corporation of Pennsylvania Filed May 5, 1959, Ser. No. 811,141.

.6 Claims. (Cl. 259-104) This invention relates to an improved methodand apparatus for intimately blending two or more discrete materials.

An accepted method and apparatus is to introduce two or more discretematerials in bulk into a tank and rotate a bladed agitator through themass of the discrete materials to be blended. For many purposes thismethod and apparatus produces a satisfactory degree of blending thoughrather time consuming. Where the requirements are more exacting, thatis, where a high degree of blending and homogeneity in the end productis desired, with substantially all agglomerated particles disintegrated,the above method and apparatus even after a prolonged time does noteffect a satisfactory result. To meet such more exacting requirements,it has been necessary to employ more elaborate and expensive equipment.

An object of my invention is to provide an apparatus of the agitatortype described above embodying means whereby the time required forintimately blending the several discrete materials is materiallyreduced, and wherein a more uniform and homogeneous blend of thematerials is obtainable.

Another object is to provide a blender of this type that moreelfectively disintegrates agglomerated particles of the discretematerials to produce a more homogeneous blending of the materials.

Another object is to provide a blender productive of the above resultsthat is simple in construction and inexpensive to manufacture ascompared to existing apparatus for achieving similar results.

Another object is to provide a blender of the above type particularlyadapted for addition of a liquid to the dry ingredients in a manner tominimize agglomeration of the ingredients and to effect a higher degreeof dispersion of the wetting agent to obtain a more intimate andhomogeneous blend of moistened but discrete ingredient particles.

Other objects and advantages more or less ancillary to the foregoing andthe manner in which all of the various objects are realized will appearin the following description, which considered in connection with theaccompanying drawings, set forth the preferred embodiments of theinvention.

In the drawings FIGURE 1 is a side elevation of the apparatus embodyingthe invention, parts being broken away;

FIGURE 2 is a transverse sectional view taken on the line 2-2 of FIGURE1 looking in the direction of the arrows;

FIGURE 3 is a transverse sectional view of a modified form of theinvention, the section being taken through the apparatus similarly tothe section shown in FIG- URE 2;

FIGURE 4 is a side elevation of a modified form of auxiliary agitatingmeans;

FIGURE 5 is an end elevation of the agitating means shown in FIGURE 4;

FIGURE 6 is a side elevation of another modified form of auxiliaryagitating means; and

FIGURE 7 is an end elevation of the agitating means shown in FIGURE 6.

Referring to the drawings, and particularly to FIG- URES 1 and 2, theblender embodying the present invention includes a trough shapedreceptacle 10 having substantially vertical side walls 12 and 14, asemi-cylindrical bottom wall 16 and vertical end walls 18 and 20. Theblender receptacle 10 is supported up off the floor by suitable legs 22.

The bottom of the semi-cylindrical lower wall 16 is provided, midwaybetween the vertical end walls 18 and 20 of the receptacle 10, with anysuitable valve controlled discharge outlet 24, the details of which donot constitute a part of this invention and are therefore not shown inthe drawings nor described.

A primary mixing or agitating means 26 is provided in the receptacle l0and includes a shaft 28, the axis of which coincides with the center ofcurvature of the cylindrical lower wall 16. On the shaft 28 are mounteda plurality of longitudinally spaced mixing paddles 30, there being fivesuch paddles shown for purpose of illustration, though the number may beincreased or decreased depending on the length of the receptacle 10. Theshaft 23 extends through the end walls 18 and 20 and is mounted inbearings 32 and 34 supported on brackets 36 and 38 suitably secured tothe legs 22 at opposite ends of the apparatus.

Each of the mixing paddles is provided with a hub 40 secured to theshaft 28 by a set screw 42 or other suitable means. Projecting radiallyfrom each of the hubs 40 are four rods 44 spaced apart. The rods of thetwo mixing paddles 30 at the left of the central mixing paddle 30, asviewed in FIGURE 1, are preferably offset 45 with respect to each other,as are also the rods 44 of the mixing paddles 30 at the right of thecentral mixing paddle 30, for a reason to be referred to later.

Fixed to the outer ends of the rods 44 of each of the mixing paddles '30are an outer series of blades 46 disposed to follow closely the innerwall surface of the semicircular bottom wall '16 of the receptacle 10 asthe mixing paddles are rotated by rotation of the shaft 28. Also fixedto the rods 44 of each of the mixing paddles 30, approximately midwaybetween the hubs 40 and the outer blades 46 are an inner series ofblades 48.

The outer and inner blades 46 and 48 of the paddles 30 at each side ofthe central mixing paddle 30 are pitched at an angle with respect to theaxial plane of the shaft 28, with the outer and inner blades ofrespective paddles being pitched in opposite directions. The outer andinner blades, pitched in opposite directions, effect movement of thematerial in opposite directions lengthwise of the receptacle whichtogether with the rotational movement imparted to the material byrotation of the mixing paddles provides for intimate mixing of thematerials to be mixed.

With the central discharge 24, the outer blades 46 of the mixing paddles30, at each side of the central mixing paddle 30, are pitched in adirection so that with the agitating means 26 rotating in the directionof the arrows or clockwise as viewed in FIGURE 2, the material as it ismoved upwardly along the side wall 12 of the receptacle 10 is at thesame time moved inwardly from the ends of the receptacle toward thecenter. In this manner, after a batch of material has been mixed, andthe valved discharge outlet 24 is opened, it is moved toward the valveddischarge outlet 24 to facilitate emptying of the receptacle 10. Theouter and inner blades 46 and 48 of the central mixing paddle 30, whichis directly over the discharge outlet 24, are preferably disposed in aplane parallel with the axial plane of the shaft 28 to facilitatedelivery of the material to the discharge outlet.

The agitating means 26 is rotated in any suitable manner from the motoras by a sprocket chain 52 trained over sprockets 54 and 56 mountedrespectively on an extension of the shaft 28 and the motor shaft.

The preferred primary agitating means 26, above described, as well asother forms of rotating bladed agitators, effect a degree of blending ofmaterials which for many purposes may be satisfactory, however for moreexacting requirements, I have provided means cooperating with theprimary agitating means 26 effecting a high degree of blending andhomogeneity in the end product with substantially all agglomeratedparticles disintegrated.

In the form of the invention shown in FIGURE 2, the agitating means isrotated at a speed such that the centrifugal action thereof will raisethe normal level of the material along the side wall 12 but insufficientto forcibly throw any appreciable amount over toward the side wall 14.

An auxiliary agitating means 58 is mounted in the upper portion of thereceptacle along and adjacent the side wall 12 and having its peripheralenvelop extending partially within and projecting partially above thegenerally triangular space included between the side wall 12 and theperipheral envelop of the primary agitating means 26.

The auxiliary agitating means 58 includes a horizontal longitudinallyextending shaft 60 in proximate spaced relation with respect to thereceptacle side wall 12 and the peripheral envelop of the agitatingmeans 26. The shaft 60 is rotatably journaled at its ends in bearings 62and 64 carried by the receptacle and walls 18 and 20, and is driven by amotor 66 through suitable chain-and sprocket means 68.

Mounted on the shaft 60 for rotation therewith are a plurality ofmultiple armed spiders 70 spaced along the length of the shaft 60. Eachof the spiders 70 is shown as having four radially extendingequidistantly spaced arms 72, to the outer ends of which are secured thelongitudinally extending impeller bars 74. The impeller bars 74 of theauxiliary agitating means 58 are V-shaped in cross section and aredisposed on the arms 72 so that with the agitating means 58 rotating ina counter-clockwise direction, as viewed in FIGURE 2, the open end ofthe V of the impeller bars 74 dig into the material mounded up by theprimary agitating means 26 in the space between the receptacle side wall12 and the peripheral envelop of the agitating means 26. Increments ofthe material are scooped up by the impeller bars 74 and are forciblythrown by centrifugal force in a dispersed condition of temporary freeflotation against the cover 76 and the side wall 14 of the receptacle10, whereupon the energy imparted thereto is dissipated and the materialdrops down into the mass of material being blended.

The auxiliary agitating means 58 rotates at a very high rate of speed,many times that of the primary agitating means 26, so that a storm orhurricane of material is produced in the upper portion of the receptacle10, effecting an intimate mixture of the materials, and the impact ofthe particles against each other and against the cover and side wall ofthe receptacle completely disintegrates any agglomerated particles,whereby a more highly uniform and homogeneous blending of the materialsis obtained.

Where the materials being blended are to be treated by a liquid wettingagent, nozzle means 78 is provided in the upper portion of the side wall14 and is arranged to direct a spray of the liquid wetting agentcounter-current with respect to the direction of movement of thematerial by the auxiliary agitating means 58. The introduction of theliquid in the form of a spray into the storm or hurricane of materialsin the upper portion of the receptacle 10 effects a high degree ofdispersion of the wetting agent and results in a more intimate andhomogeneous blend of moistened but discrete ingredient particles.

Referring to FIGURE 3, there is shown a modified form of the inventionwherein the relative disposition and construction of the elements arethe same as in the preferred form of the invention shown in FIGURES 1and 2, so that a detailed description thereof is dispensed with. In thisform of the invention, the primary agitating means 26a is rotated at aspeed so that the materials being mixed and blended are thrown bycentrifugal force across the upper portion of the receptacle 10a fromadjacent the side wall 14a toward the side wall 12a, the agitating means26a being rotated in a direction opposite the rotation of agitatingmeans 26 of the first form of the invention. The particles of materialare thrown into the zone of action of the auxiliary agitating means 58awhich is arranged to rotate in a direction opposite the direction ofrotation of the primary agitating means 26a. The auxiliary agitatingmeans 58a is arranged to rotate at a higher speed than the primaryagitating means 26a. The particles inter cepted by the auxiliaryagitating means 53a are violently struck and impelled toward thereceptacle side wall 14a which together with the impact of the collidingparticles, completely disintegrates any agglomerated particles andeffects a uniform and homogeneous blending of the materials.

In FIGURES 4 and 5 is shown a modified form of the auxiliary agitatingmeans wherein a plurality of closely spaced multiple armed spiders 80are secured along the length of the shaft 32. Each of the spiders 80 isshown as having four radially extending equidistantly spaced arms 84.

In FIGURES 6 and 7 is shown still another form of the auxiliaryagitating means wherein the shaft 86, corresponding to the shaft 60 onthe form of the invention shown in FIGURES 1 and 2, is provided at itsends with disks 88. Disposed in radial spaced relation about the shaft86 are a plurality of longitudinally extending rollers 92, the ends ofwhich are provided with pins 94 extending into radially elongated slots96 disposed in circumferentially equidistantly spaced relation near theperiphery of the disks.

The rollers 92 are moved to their outermost radial position bycentrifugal force upon rotation of the shaft 86, in which position theyare arranged to engage the side wall of the receptacle, whereby theparticle size of the materials are caused to be finely divided.

As in the case of the auxiliary agitating means of the preferred form ofthe invention, the auxiliary agitating means of FIGURES 4 to 7, providesin the upper portion of the receptacle a zone of intense turbulentaction to effect comminution and breaking up of agglomerated particlesand a thoroughly uniform and homogeneous blending of the materials.

While the apparatus is shown and described herein as a batch apparatus,it is apparent that materials to be blended may be continuouslyintroduced into one end of the receptacle and the blended materialsdischarged from the other end. In this case, the outer blades 46 of themixing paddles 30 are preferably all pitched in a direction to move thematerials toward the discharge end of the receptacle while the innerblades 48 are pitched in the opposite direction.

Although I have disclosed various exemplary embodiments of my inventionherein for the purposes of illustration, it will be understood thatvarious changes, modifications and substitutions may be incorporatedtherein without necessarily departing from the spirit of the invention.

I claim:

1. In an apparatus for blending discrete materials, a closed tank havingan arcuate bottom merging into upright side walls and confining a chargeless than the capacity of said tank, a bladed agitator mounted withinthe lower portion of said tank for rotation about a horizontal axis insaid charge of said discrete materials, said arcuate bottom wall closelyfitting the lower portion of the peripheral envelope of said agitatorand said upright side walls being in receding relation with respect tothe upper portion of the peripheral envelope of said agitator, means forrotating said agitator, the blades of said agitator being formed tocooperate with the walls of said tank to raise said discrete materialsalong one upright side wall above the normal level of the material insaid tank, an impeller disposed in the upper portion of said tank abovethe normal level of the discrete materials therein for rotation about anaxis parallel with respect to the axis of said agitator and with itsperipheral envelope disposed adjacent said one upright side wall betweensaid one upright side wall and the axial vertical plane of said agitatorand adjacent the peripheral envelope of said agitator, said impellerhaving impelling means disposed in a plane parallel with respect to thelongitudinal axis of said tank to rotate into and engage and movediscrete material delivered thereto by said agitator in a directiontransversely of the axis of rotation of said impeller, and means forrotating said impeller in a direction and at a speed to propel saidengaged material in said transverse direction over said agitator throughsaid upper portion of the tank normally devoid of discrete materials inan air borne dispersed condition of temporary free flotation from saidone side Wall toward the opposite side Wall of said tank.

2. An apparatus for agitating and blending discrete materials comprisinga unitary trough-shaped tank having an arcuate-shaped bottom merginginto upright side walls, agitating means positioned within the lowerportion of said tank for rotation about an axis coinciding with thelongitudinal axis of said tank, means for rotatably driving saidagitating means, said agitating means being in close proximity to saidbottom and side Walls of said tank for mixing at low speed materialwithin said tank and formed for simultaneously delivering portions ofsaid mixed material to an upper zone along a side wall of said tankabove the normal material level therein, impelling means positionedwithin the upper portion of said tank substantally co-extensivetherewith and adjacent said side wall, said impelling means havingimpeller elements disposed in planar parallelism with respect to thelongitudinal axis of said tank, and means for rotatably driving saidlast-mentioned means for engaging said material raised along said sideWall and impelling said material transversely across said tank over saidagitating means at high speed in temporary free flotation.

3. In an apparatus for blending discrete materials, an elongated closedtrough shaped tank having upright side Walls and an arcuate bottom andconfining a charge of materials less than the capacity of said tank, abladed agitator extending the length of said tank and mountedlongitudinally therein contiguous to the arcuate bottom of said tank forrotation about a horizontal axis in said charge of materials, animpeller extending the length of said tank and mounted in the upperportion thereof above the normal level of the materials therein in axialparallelism with respect to said agitator and between one upright sidewall of said tank and the axial vertical plane of said agitator, meansfor rotating said agitator, said agitator being formed to move thematerials laterally toward one side wall of said tank and to cooperatewith said side wall to raise said materials therealong above the normallevel of the materials in the tank and into the zone of action of saidimpeller, said impeller having impeller elements disposed in a planeparallel with respect to the longitudinal axis of the tank to engage andpropel materials delivered thereto by said agitator in a directiontransversely of the axis of said impeller and the longitudinal axis ofthe tank, and means for rotating said impeller in a direction and at aspeed to propel said engaged materials in said transverse directionacross said upper portion of the tank and over said agitator in an airborne dispersed condition of temporary free flotation from one side walltoward the opposite side wall of the tank.

4. In an apparatus for blending discrete materials, an elongated closedtrough shaped tank having upright side walls and an arcuate bottom andconfining a charge of materials less than the capacity of said tank, abladed agitator extending the length of said tank and mountedlongitudinally therein contiguous to the arcuate bottom thereof forrotation about a horizontal axis in said charge of materials, the bladesof said agitator being formed and rotating in a direction to move thematerials laterally toward one side Wall of said tank and to cooperatewith said wall to raise the materials upwardly therealong above thenormal level of the materials in said tank, means for rotating saidagitator at a speed to propel successive fractions of said raisedmaterials in a dispersed condition of free flotation in a transversedirection across the upper portion of said tank from said one side walltoward the opposite side wall thereof, an impeller extending the lengthof said tank and mounted within the upper portion thereof adjacent saidopposite side wall for rotation about an axis parallel with respect tothe axis of said agitator and disposed in the path of the air bornematerials propelled by said agitator, said impeller having impellerelements disposed in a plane parallel with respect to the longitudinalaxis of said tank to engage and propel materials delivered thereto bysaid agitator in a direction transversely of the axis of said impeller,and means for rotating said impeller at a higher speed than saidagitator and in a direction for propelling intercepted air bornematerials in said transverse direction opposite said first nameddirection to efiect violent impingement of materials against each other.

5. A method of blending a mixture of discrete materials, comprisingintroducing a charge of said materials in a closed elongated troughshaped container, the charge being less than the capacity of thecontainer to normally provide therein a lower zone of said materials andan upper zone devoid of said materials, imparting a rotating agitatingmotion to the mass of materials about a horizontal axis extendinglongitudinally of the container for mixing the same and elevatingsuccessive portions of the materials along one side of said horizontalaxis into and at one side of the upper zone normally devoid ofmaterials, and then further mixing and blending said materials r byviolently propelling said successive portions of elevated materialsthrough said upper zone in a direction normal to the said horizontalaxis from said one side to the opposite side of said upper zone over themass of materials mixed in said lower zone in an air borne dispersedcondition of temporary free flotation for deposition on andincorporation into the mass of material being mixed in said lower zone.

6. A method of blending a mixture of discrete materials, comprisingintroducing a charge of said materials in a closed elongated troughshaped container, the charge being less than the capacity of thecontainer to normally provide therein a lower zone of said materials andan upper zone devoid of said materials, imparting a rotating agitatingmotion to the mass of materials about a horizontal axis extendinglongitudinally of the container for mixing the same and elevatingsuccessive portions of the materials along one side of said horizontalaxis into the upper zone normally devoid of materials along one side ofthe container and propelling them through said upper zone in an airborne dispersed condition toward the opposite side of the container,intercepting the propelled materials at said opposite side of thecontainer and propelling them at a higher speed through said upper zonein an air borne dispersed condition in a direction normal to the saidhorizontal axis and opposite the first direction of propelling thematerials to effect violent impinge ment of particles of materials uponeach other in said upper zone.

References Cited in the file of this patent UNITED STATES PATENTS 8Thatcher June 5, 1923 King Sept. 10, 1929 McAllister Mar. 31, 1953 WolfeApr. 20, 1954 Madsen Nov. 25, 1958 Bridges Aug. 2, 1960 FOREIGN PATENTSSweden July 22, 1947 OTHER REFERENCES Steiner et al.: German printedapplication H10650, Oct.

5. A METHOD OF BLENDING A MIXTURE OF DISCRETE MATERIALS, COMPRISINGINTRODUCING A CHARGE OF SAID MATERIALS IN A CLOSED ELONGATED TROUGHSHAPED CONTAINER, THE CHARGE BEING LESS THAN THE CAPACITY OF THECONTAINER TO NORMALLY PROVIDE THEREIN A LOWER ZONE OF SAID MATERIALS ANDAN UPPER ZONE DEVOID OF SAID MATERIALS, IMPARTING A ROTATING AGITATINGMOTION TO THE MASS OF MATERIALS ABOUT A HORIZONTAL AXIS EXTENDINGLONGITUDINALLY OF THE CONTAINER FOR MIXING THE SAME AND ELEVATINGSUCCESSIVE PORTIONS OF THE MATERIALS ALONG ONE SIDE OF SAID HORIZONTALAXIS INTO AND AT ONE SIDE OF THE UPPER ZONE NORMALLY DEVOID OFMATERIALS, AND THEN FURTHER MIXING AND BLENDING SAID MATERIALS BYVIOLENTLY PROPELLING SAID SUCCESSIVE PORTIONS OF ELEVATED MATERIALSTHROUGH SAID UPPER ZONE IN A DIRECTION NORMAL TO THE SAID HORIZONTALAXIS FROM SAID ONE SIDE TO THE OPPOSITE SIDE OF SAID UPPER ZONE OVER THEMASS OF MATERIALS MIXED IN SAID LOWER ZONE IN AN AIR BORNE DISPERSEDCONDITION OF TEMPORARY FREE FLOTATION FOR DEPOSITION ON ANDINCORPORATION INTO THE MASS OF MATERIAL BEING MIXED IN SAID LOWER ZONE.